Keep in mind that you will need 3 mono cables to trigger all three amps. Why not at least try the audio trigger? Also Outlaw doesn't recommend trying to trigger more than two in series. This note is in the 2200 manual:

Note: Connecting more than two Model 2200s to a single source controller
may overload the system and is not recommended. If you wish to
automatically turn on more than two Model 2200 units, we recommend
the use of either the music sense circuitry or an externally powered relay
controller. Contact Outlaw Audio Customer Service for more information
on using the Model 2200 in multiple unit systems to avoid damage to
your processor, receiver or controller.